docs: def reverse_set_ipv6(self, subid, ipaddr, entry, params=None):
          ''' /v1/server/reverse_set_ipv6
          POST - account
          Set a reverse DNS entry for an IPv6 address of a virtual machine. Upon
          success, DNS changes may take 6-12 hours to become active.
  
          Link: https://www.vultr.com/api/#server_reverse_set_ipv6
          '''
          params = update_params(params, {
              'SUBID': subid,
              'ip': ipaddr,
              'entry': entry
          })
          return self.request('/v1/server/reverse_set_ipv6', params, 'POST')